The present invention relates to a photoresist composition suitable for lithography utilizing high-energy radiation such as a far ultraviolet ray including eximer laser, electron beam, X-ray, radiation or the like.
Recently, with development of higher integration of an integrated circuit, formation of a submicron pattern is required. Eximer laser lithography has attracted special interest for such a requirement, particularly for it enables production of 64 MDRAM and 256 MDRAM. As a resist suitable for such eximer laser lithography process, a so-called chemical amplifying type resist has been suggested which utilizes an acid catalyst and chemical amplifying effect. In the chemical amplifying type resist, solubility of portion irradiated with a radiation in an alkaline developer is changed through a reaction utilizing an acid catalyst generated from an acid generator in the irradiated portion, and by this, a positive or negative pattern is obtained.
In the chemical amplifying type positive resist, an acid generated in the irradiated portion diffuses by post heat treatment (post exposure bake: hereinafter, abbreviated as PEB), and acts as a catalyst for changing solubility of irradiated portion in a developer. Such a chemical amplifying type resist has a defect that it is liable to be influenced by the environment. For example, it is known that performances thereof change depending on the standing time from irradiation to PEB, which is referred to time delay effect. The time delay effect not only decreases the resolution but also generates a layer poorly soluble in an alkaline developer on the surface of a resist film and lowers the size reproducibility of pattern by making pattern after the developing in T shape. It is said that the time delay effect is caused by deactivation of an acid generated in a resist by a small amount of ammonia or amines existing in environmental atmosphere.
To suppress such a time delay effect, namely to increase time delay effect resistance (hereinafter, abbreviated as TDE resistance), it is known to added a nitrogen-containing compound to a chemical amplifying type positive resist as a quencher. By this addition, TDE resistance increases to a certain extent. However, the increase in TDE resistance and resolution are not sufficient when a conventionally known nitrogen-containing compound is used as a quencher.